I also had an occasion where someone claimed I didn't represent the item properly (I did) and demanded money back plus all shipping fees even though I had a No Returns policy on the item as it was not an expensive item. I fulfilled that request at cost to me, but didn't leave negative feedback. Instead I just blocked the person from bidding on any of my items in the future.
By and large, I've been very satisfied with the Ebay transactions I've made.
I have never had a bad experience with an eBay seller; I even bought a car on eBay and it was the best car buying experience I’d had in years.
The only problems I have ever had have been with PayPal charging twice for the same transaction and then being completely unresponsive about it. I worked it out with the seller who was great but I don’t think I’ll be using PayPal anymore.